Kayakujutsu

Kayakujutsu  (Kanji 火薬術? )  (literally the art of gunpowder) is the use of  firearms,  gunpowder and  explosives especially by  Ninja. The history and mythology surrounding ninjutsu and kayakujutsu are similar to the history of chemistry and the mythology surrounding  Alchemy. Thus kayakujutsu mysticism refers to  elements like the Earth (Chi) to develop Fire (Kaji) just as alchemy referred to  elements just as air, earth, fire and water.